As will be appreciated by those skilled in the art, specialized helical shaped devices such as screw conveyors are well known for the transport of various bulk material. Such conveyors generally include a helical shaped member which rotates within a housing or trough such that rotation of the screw conveyor along its longitudinal or central axis results in movement of the bulk material along the length of the device. In the past, such conveyors were typically constructed from metal and each conveyor was specifically designed for a particular purpose and of a particular length. However, although most prior art conveyors were specifically designed to meet a particular application, there had been some attempts of providing a modular type conveyor of metal and/or wood. Examples of U.S. Patents which disclose such modular conveyors include U.S. Pat. Nos. 349,233 issued to James Nelson on Sept. 10, 1886; 455,384 issued to H. Birkholz on July 7, 1891; 525,194 issued to J. Dyson, et al on Aug. 20, 1894; 546,879 issued to J. Dyson, et al on Sept. 14, 1895; 1,867,573 issued to D. G. Leach on July 19, 1932; 2,492,915 issued to A. B. Carlson on Dec. 27, 1949; 3,648,826 issued to Dean P. Brooks on Mar. 14, 1972 and 3,705,644 issued to Claude E. Kawchitch on Dec. 12, 1972. However, a study of the above patents indicates that only the two Dyson, et al patents, the Nelson patent and the Kawchitch patent can be considered sectional or modular. In addition, the assignee of the present application filed an application for Letters Patent on Sept. 29, 1983 for a "Modular Screw Conveyor" and which has Ser. No. 537,345 now abandoned, and on Apr. 4, 1984 filed and application for "Mold and Process for Manufacturing Helical Shaped Items" which has Ser. No. 598,374 now U.S. Pat. No. 4,693,861. An application entitled "Concealed Drive Coupling for Use With Modular Screw Conveyor" and having Ser. No. 822,641 was filed on Jan. 27, 1986 now U.S. Pat. No. 4,691,818. This application is also assigned to the assignee of the present invention.
In addition, it is believed that apparatus is available for bonding sections of plastic pipes together in a fluid or liquid tight manner by heating the ends and pressing the melted ends together. However, although there is similarity between the techniques of bonding tubular plastic sections together, the specific components, techniques and the overall concept as applied to bonding modular screw conveyor sections together is believed to be unique and different from that of bonding plastic pipe together.
As will be appreciated, one of the advantages of the plastic modular screw conveyor is ease of cleaning due to the smooth and noninterrupted surfaces. Also of course, by axially stacking any selected number of modules on the non-circular drive shaft a screw conveyor of any length can be fabricated. For certain USDA applications, the assemblage of individual modules must be sealed to each other at the end surfaces of the hub or axial members of each module to eliminate any cavities etc. which might harbor bacteria, and also to prevent the transmission of bacteria or liquids from the outside of the screw conveyor into the metal drive shaft area.
Therefore, it is an object of the present invention to provide apparatus and methods for joining or bonding the axial end of one module to the axial end of a second module in a fluid tight manner.
It is another object of the present invention to provide apparatus and methods which results in a bond or joint such that the joined members are axially aligned.
It is yet another object to provide apparatus and methods which allows a multiplicity of modules to be joined together.